Driver core: make old versions of udev work properly

If CONFIG_SYSFS_DEPRECATED is enabled, old versions of udev will work
properly with devices that are associated with a class.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 45 insertions, 14 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index dbcd40b987d2..8f8347b9197f 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -384,6 +384,19 @@ void device_initialize(struct device *dev)
         device_init_wakeup(dev, 0);
 }
 
+#ifdef CONFIG_SYSFS_DEPRECATED
+int setup_parent(struct device *dev, struct device *parent)
+{
+        /* Set the parent to the class, not the parent device */
+        /* this keeps sysfs from having a symlink to make old udevs happy */
+        if (dev->class)
+                dev->kobj.parent = &dev->class->subsys.kset.kobj;
+        else if (parent)
+                dev->kobj.parent = &parent->kobj;
+
+        return 0;
+}
+#else
 static int virtual_device_parent(struct device *dev)
 {
         if (!dev->class)
@@ -401,6 +414,22 @@ static int virtual_device_parent(struct device *dev)
         return 0;
 }
 
+int setup_parent(struct device *dev, struct device *parent)
+{
+        int error;
+
+        /* if this is a class device, and has no parent, create one */
+        if ((dev->class) && (parent == NULL)) {
+                error = virtual_device_parent(dev);
+                if (error)
+                        return error;
+        } else if (parent)
+                dev->kobj.parent = &parent->kobj;
+
+        return 0;
+}
+#endif
+
 /**
  *      device_add - add device to device hierarchy.
  *      @dev:   device.
@@ -423,23 +452,18 @@ int device_add(struct device *dev)
         if (!dev || !strlen(dev->bus_id))
                 goto Error;
 
-        /* if this is a class device, and has no parent, create one */
-        if ((dev->class) && (dev->parent == NULL)) {
-                error = virtual_device_parent(dev);
-                if (error)
-                        goto Error;
-        }
+        pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);
 
         parent = get_device(dev->parent);
 
-        pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);
+        error = setup_parent(dev, parent);
+        if (error)
+                goto Error;
 
         /* first, register with generic layer. */
         kobject_set_name(&dev->kobj, "%s", dev->bus_id);
-        if (parent)
-                dev->kobj.parent = &parent->kobj;
-
-        if ((error = kobject_add(&dev->kobj)))
+        error = kobject_add(&dev->kobj);
+        if (error)
                 goto Error;
 
         /* notify platform of device entry */
@@ -484,8 +508,11 @@ int device_add(struct device *dev)
         if (dev->class) {
                 sysfs_create_link(&dev->kobj, &dev->class->subsys.kset.kobj,
                                   "subsystem");
-                sysfs_create_link(&dev->class->subsys.kset.kobj, &dev->kobj,
-                                  dev->bus_id);
+                /* If this is not a "fake" compatible device, then create the
+                 * symlink from the class to the device. */
+                if (dev->kobj.parent != &dev->class->subsys.kset.kobj)
+                        sysfs_create_link(&dev->class->subsys.kset.kobj,
+                                          &dev->kobj, dev->bus_id);
                 if (parent) {
                         sysfs_create_link(&dev->kobj, &dev->parent->kobj, "device");
                         class_name = make_class_name(dev->class->name, &dev->kobj);
@@ -623,7 +650,11 @@ void device_del(struct device * dev)
         }
         if (dev->class) {
                 sysfs_remove_link(&dev->kobj, "subsystem");
-                sysfs_remove_link(&dev->class->subsys.kset.kobj, dev->bus_id);
+                /* If this is not a "fake" compatible device, remove the
+                 * symlink from the class to the device. */
+                if (dev->kobj.parent != &dev->class->subsys.kset.kobj)
+                        sysfs_remove_link(&dev->class->subsys.kset.kobj,
+                                          dev->bus_id);
                 class_name = make_class_name(dev->class->name, &dev->kobj);
                 if (parent) {
                         sysfs_remove_link(&dev->kobj, "device");